Nausea and vomiting are commonly and severely debilitating adverse events of cytotoxic chemotherapy, radiotherapy, and certain types of surgeries. These symptoms limit patients' ability to eat and drink, remarkably reduce quality of life, threat the success of therapy (Sussman N, Anticancer Drugs 1995; 6(suppl 1):4-8). It has been reported that up to 20% of patients were forced to postpone or refuse potentially curative treatment (Herrstedt J, Support Care Cancer 2002; 10:85-87). The management of chemotherapy-induced, radiotherapy-induced, and postoperative nausea and vomiting (CINV, RINV, and PONV) has improved greatly recently with the introduction of 5-HT3-receptor-antagonists (5-HT3-RAs) (Jordan K et al., Critical Reviews in Oncology/Hematology 2007; 61:162-175). The 5-HT3-RAs, also known as “setrons”, are widely regarded as the most efficacious antiemetics available today and currently recommended as the first choice to control CINV, RINV and PONV (Annual Oncology 1998; 9:811-819).
Granisetron (1-methyl-N-((1R,3r,5S)-9-methyl-9-azabicyclo[3.3.1]nonan-3-yl)-1H-indazole-3-carboxamide; CAS No.: 109889-09-0) is a potent and highly selective 5-HT3-RA, it is effective and well-tolerated for preventing CINV, RINV and PONV (de Genolier C G, The Oncologist 2004; 9:673-686).

The available dosage forms of granisetron in the market include oral tablet/solution (Kytril®), transdermal patch (Sancuso®), and intravenous injection (Kytril®). The onset of oral tablet or transdermal patch, however, is relatively slow (at least 1 hour for PO route and 24 hrs for transdermal route), and oral dosing of the tablets may be extremely difficult when patients are suffering from nausea and vomiting and the swallowing capacity is compromised. Granisetron IV injection can achieve rapid pharmacological effect (5 minutes), however, it is invasive and patients will suffer unnecessary pains and potential side-effects related to the injection, not to mention the extra staff time and procedure involved in administer the injectable medication. Therefore, it is imperative to seek an alternative dosage form that is ease of use, non-invasive, safe with rapid onset for better manage.
In light of the aforementioned limitations of oral, transdermal and injectable granisetron products, there is a need for an alternative route of administration, for example, there being interests shown in intranasal administration. Intranasally absorbed melatonin will directly enter into systemic circulation, and the first-pass hepatic metabolism is completely avoided (Bechgaard E et al., Int J Pharm 1999; 182:1-5). Meanwhile, the nasal mucosa has less proteolytic activity than the gastrointestinal tract (Zhou X H and Po L W, Int J Pharm 1990; 68:241-250), thus both rapid pharmacological onset and high bioavailability are expected to achieve after intranasal administration. Intranasal delivery is also ease-of-use, safe, and allow patient self-dose as needed. Granisetron is a small and lipophilic molecule with acceptable water solubility and stability; compared to other setron drugs (i.e. ondansetron), the dose of granisetron is low (1-2 mg/person/day), therefore, it is a possible candidate for intranasal delivery. However, up till now, nobody was able to come up with an effective formulation that works for intranasal delivery.
Due to nasal mucociliary clearance, substances administered intranasally are rapidly removed from the nasal cavity, with the mean clearance half-life of approximately 21 min (Soane R J et al., Int J Pharm 1999; 178: 55-65). MCC may result in short nasal residence time, limited drug absorption and insufficient pharmacologic effect (Ugwoke M I et al., J Pharm Pharmacol, 2001; 53, 3-22).
Intranasal composition comprising granisetron was firstly disclosed in CN patent no. ZL021176716.8. Granisetron hydrochloride, together with preservatives and tonicity agents, were dissolved in water and then filtrated and filled into spray device. After intranasal administration of the solution formulation in beagle dogs, the drug plasma concentration (Cmax) increased 1.5-5 fold as compared to that after administration of oral tablets. The time to reach Cmax (Tmax) was reduced from 1.5 hr (oral) to 0.31 hr (intranasal). However, the relatively bioavailability (intranasal to oral) was only 111.88%, indicating that drug solution was rapidly removed by nasal mucociliary clearance (MCC) after intranasal administration, resulting in low systemic exposure (AUC) despite of much higher Cmax.
The mucoadhesive technology utilizes the bioadhesive properties of certain water-soluble polymers, which become adhesive on hydration, and hence can be used for targeting a drug to a particular region of the body (i.e. epithelial tissue) for extended periods of time (Asane G S et al., Drug Del Ind Pharm, 2008; 34, 1246-1266).
U.S. Pat. No. 7,947,257, incorporated herein by reference, disclosed the compositions containing chitosan (a salt or derivative) for intranasal administration of granisetron or the pharmaceutically salts. Chitosan is a cationic polymer with bioadhesive properties, has been shown to improve the systemic bioavailability of granisetron after intranasal administration in sheep, with shorter time to maximum plasma concentration (Tmax). This composition, unfortunately, cause nasal irritation and painful sensation and is not suitable for human use.
U.S. Pat. No. 8,827,946, incorporated herein by reference, and descripted a dry powder granisetron composition for intranasal delivery. To deliver accurate and sufficient amount of powder into nasal cavity, a complicated and costly spray device by compressed air was utilized. The spray dose uniformity and reproducibility, unfortunately, are poor, with high risk of inhalation into lung. The physicochemical stability of dry powder is more susceptible to the environmental humidity. Furthermore, nasal irritation induced by the high local drug concentration where the drug powder accumulates is a common issue after intranasal delivery of powder formulations.
In view of the issues existed in the prior art, there is a clear need for a new and special composition with controlled and prolonged drug release when sprayed onto nasal mucosa, reduced the stinging sensation, improved and sustained anti-vomiting/nausea effects.